An absent-minded person who needs to remember to do an errand on the way to work may choose to drive an unaccustomed route, knowing that if he drives his usual route he will pursue his usual thoughts and nothing will remind him along the way of the errand he must stop for, while an unaccustomed route will continually remind him that there is some reason for his being in strange surroundings.

Thomas Schelling, ‘Enforcing Rules on Oneself’, Journal of Law, Economics, and Organization, vol. 1, no. 2 (Fall 1985), p. 361